Steam engine valve gear



Jan. 1, 1935.

F. TOLKIEN STEAM ENGINE VALVE GEAR Filed Feb. '7, 1950 6 Sheets-Sheet 1 Jan. 1, 1935. F. TOLKIEN 1,986,083

vSTEAM ENGINE VALVE GEAR Filed Feb. 7Q 1930 e Sheets-Sheet 2 .\fram main 511df+ ,frzvelzi'or Jan. 1, 1935. F. TOLKIEN STEAM ENGINE VALVE GEAR 7 Filed Feb. 7, 1930 6 Sheets-Shet 3 5 :0 2 6 rtp zizvnll'ar Jan. 1, 1935. TbLKlEN I 1,986,083

STEAM ENGINE VALVE GEAR Filed Fat :7, 1930 e Sheets-Sheet 4 b k main :bwf/

a. woman Jan. 1, 1935. F. TOLKIEN STEAM ENGINE VALVE GEAR Filed "Feio" '7, 1950 e SheetsSheet 6 ass y JUNITED OFFICE ipsaos sq" l i Q U" I vs'tvi: I

" ili fo kie e ewemm Fsa'f 1:;1931);serialN6.26,656 M 6 1 .9; I

My application of the 27th- Misty- 1929 ;v ament being such that the main slide'valve first I 366,394 relates to steam engines'withsfluidiop'ereq brought into a position in which itcuts off both ated valves, in which ateachsend; of *thewalve; thexsteam. admission on the side of the piston a fint al piston, thatis to .say a smallt'andv which is under fluid pressure andthesteam ex-,'

' a large pistonwas,provided which:foperatesin thaust on'the side of the piston which .is not 5 corresponding spacesthe valve easingtherebyxunder fluid pressure, whereupon after dwelling imparting motion to the actual main slide valve; =f0r'a shorter or longer period inthisposition it In these known steam enginesthe steamwas sup-s completes its motion up, to its extreme position;

plied to the differential pistons orrtheir reversing It is obvious that by s regulation the Slide spaces byqthe motion of the'main slide; valve avalve'motionyin its second stage "it is'possible to 3 The invention in my earlier applicatiomg ser 55 treme position; being subdivided;thearrange+- being divided into two stages; The} main slide obt inanyr deSiTBd d ee DI O 1 valve first moves into the position 'inwhichuits Figure-l shows the beginning ofathe admission cuts off the steam supply, to they-power cylinder; of steam to the righthand end of thecylinder, the sothat the expansion will commence in thepower; working piston being situated at this end of the cylinder. This determines the;admissionxtopthewcylinder; Figure-2'shows' the beginningof the power cylinder (cut-offposition);-; In 'this-posi-Rexpansionficut off positio-nL'I Figure.-3. Sh ws the 3 tion, however, the outlet stillremains, open -on beginning of compression on the lefthand side of;

the side of the power piston not --under;fluid prestheworking piston. Figure 4 shows't-he beginning sure, so thatthe used steam will continue to be 1 of admission on the left hand and oi-theicylinder,v expelled I j 1: I

' 0n the main slide valve, owing to steambeing ,sthe cylindern Figure 5showsthe beginning of admitted to the differential pistons, passingin' .expansionof the steam'admitteditothe left hand thesecond stage of its motion out of this cut-off :side ofxthe piston; (cut oif position): Figure 6 position, it will first cut oif the steam:outlet;on "shows the-beginning: of compress'ion'oflthesteam;

the side'of the power, piston not under fluidpprese on ithe right. hand sidehof .thewworking' piston. sure, so that on this side the compressionswill 1' In th8Se figures the main slide valve hassubstaneji commence, a d W111 y,; t reaching?v itS ltially=the same form as in myearlie'rapplicationi I extreme position, re hestea s pplvz-tmthe SeraNo." 366,394. On.-the;rod d, are mountedthe power cylinder. i itwo slide valvebodies d and d and the differ-,

3 consists tan i y in e ulatin -reversing spacespf, f f 'f 'of the valve'casing c. the supply of the steam acting on; the differential p on of t a n l e eo hini e-hrst. sta e of its m t n forregulating he dmi qn' various places thatthe differential pistons 'e e its motion f a net m s n' to shut off spaces therein. Consequently, the

power Cylinder y l -r opp va v sso r;.-va1ve casing 'c' and'the said pistons formthe rethe likei versing spaces while the pistons operatetherein- AS already Stated in these known s m re The power cylinder a is provided with the ports .the working piston: being situated at that end'of 2U ential pistons e,fe e eewhich operate inthe v In connection" with theforegoing it ,is1:tobe noted- Y 'that'the'bvalvecasing mustbe so designed-'at-the V 5 the e er and h QDd' Q iQ O e e canbear against the valve'wallsjin order 40 ines the mp n on t ecith p ston s a d. which serve bothfor steam admission-4 which is not under u r u lvw nce and for'exhaust; The steam supply to the power w the main Slide Valve h t t e s e mw cylinder atakes place at E betweentheslidevalve; outlet after the commencement. of: the second di'e d yd whilethe steam exhaust through stage of motion. Thecompressionis thus mm 'the aperture ABA? at the two' iends of the valve) .ited as regards time to the period; from-ythe i g a l v moment of this cut-off to the moment whenthes, For-regulating the admission'and the compresmain slide valve arrives atvthe end' of its motion; sion pilotvalves are provided which differ from The object of my present invention is to.;s'o1ve:l-the constructional'formin the application Seri'No. the problem of making the Compression-reigula- .-366,394,- the pilot'valve S serving for regulating tion finer so that any degree of. compression can i the admission being connected by the pipes 17% ml "50 1 actually be obtained Without difiiculty This is with the reversing, spaces f ff of the main pilot effected according to the invention by the second valve and admitting steam into these spaces alter stage of motion of themainslide valvein which knately; w I l I I y it travels fromits cut-oif -position --into its ex To the pilot valve S are connected the pipes 7& leading to the reversing spaces f, f and 'als'o the outlet r so that by moving this pilot valve the compression is regulated. The valve S controls the steam inlets m m which admits the steam in the reversing spaces F F on both sides of the valve and thereby at each end of the piston stroke either the differential piston e or e The valve S operates in the same manner as the corresponding valve S of the application 366,394. The regulationof the compression -by -means of the valve 31* follows from thedescription of the operation of the device as hereinbefore stated. The pilot valves S and S are connected with one another by a pipe 1' The steam.distribut.- ing valve t is connected to the live steam supply pipe V and is provided with the exhaust 11 9 and communicates with the pilot valve S through the pipes T and T The control pilot valves S and S and 'the steam distributing slide valve t are in ;this case actuated by oblique cams 1,2, 3. The direction of admission and rotation may be 'changedi'by:

being supplied with live steam through the passage T which is led to the reversing space 1 through the pipe 11. from the pilot valve S The controlling pipes r, n and r communicate through the pilot valves S and t with the exhaust r so that the dashpot piston e" is relieved of the direct steam pressure. Live steam passes through the steam inlet aperture E and through the steam :inlet passage a "into the cylindercand'imoves the) powerpiston b to the left. a In this position of the valve, the pipe m is not Jicovered by the controlling piston e so that the controllingsteam can flow from the space 1 into the pipe m.Since, however, the pipe m is cov- =z eredebysthe pilot valve S the controlling steam is, unable to escape The advantage of this ar- 2-rangement'is"that the-controlling piston e on the'leftand'the controlling piston e on the right ,i:hand-;.-sider?can be made shorter, whereby the weight of the valve is reduced.

.Figurei 2' 3sh'ows' the position" of the 1 parts a in whichithe 'steam admission has ceased and expans'ionicommen'cesizl By vmeansof the rotating i' camzsliaft'w which is rotated positively by means f of gearing-drivenTbyE'theJmain :driving shaft; of

therengineytheipilotwa'lve S 15 actuated by the cam: 1 andfzmoved into'ithe position shown in adapted to rotate'on a fixed pivotiso that wh'en "which:it1allows steamadmittedto the pilotvalve 3 V fromithe steam :inlet opening. '0 through the pipes placed on' the shaft for effecting'lthe desired't 'r 'and r to passtiintdthe pi.pe m whereby the these levers w w rock,1th'e cams 1, 2, 3.areldischangein the direction of admissionahd'rotation. The cams 1 2, 3 are connectedrtoitheishaft iwaby slot and' key as indicated in thefiguresisdthat piston e2? oni the'right'thand side I is supplied with" steam-s; Thetmain' tva'lve 'now-"moves to "the left it i untlllzfthefrabutment': .pistone bears against the they-are adapted tobe displaced on theishaftlb'utiileft handisid iofithe dashpot :piston e ,the pisare rotated bythe same; 'Thevalves 'S S "andstons etiand' elrremaining in the'respective'posialso i the steam-distributing vvalvetl ribeaiw'withxtionstheymave hitherto occupied. By thismovero11ers,- balls orthe like against the cams andi lme'nt 50f themain -valv'e' :to the left;- the steam pasare pressed against" the cams -in .the knowniman ner by springs.

Nowinorder to subdivideitheisecondzstageiof 1 Isa-gen? Tclosed by" the piston d while themes- 2' sage 11 *Ir'em'ains s'till opem The admission 'of the main slide valve motion in'iaccordanceiw-ith commenees of* the stean'i in th e' cylinder to the the present invention for thepurpose 10f iobtain ing a finer regulation of the conipressionQxth dashpot piston 6 ofi the main: application'-Ti equipped with an'abutment piston "e which iniits turn works in a seeondfloating dashpot ipistonte. The latter is of: largerdiameterithani theidashpo flows out to the exhaust. H Figure'3 shows th'e commencement'of the com cam shaft w, the oam 2} thereon' 'moves the pilot steam to the cylinder is at an end and expansion pre'ssiorrfi During" the further rotation' of the piston e moving in the 'space f and imovesinratmpiston s it until it-'occupies thepositionshown in space in the slide valvemasihgic:directly iad=!"'Fig. 3 in which it allows steam to pass through" joining the space F! Into the righthand end'tofi. the: pipes -n and r intothe"reversing spaces f the space i there opens aipipe T which isnzorr- 2.:and T-The steam in the reversing space i acts nected-to' the steam. distributing'slide"valve::,t onthe' right hand'side of the piston e se -"that and: is placed inconnectioniwiththe latter-:alter the main} slidev'alveagain= moves for a certain nately with the 'live steam pipe Vand ithe' steam' xdistance to the left; "The ==reversingspaces f exhaust r Thelcontroll'ingi steam entering the i and f ar evacuated through "the pipes'r and n li v v Space f thr h h pipe r at thewithrough 'the' va1ves and'the'ouflet r This same time i supplies steamcto: the left-hand 2 side ti moveme'nt tothe left-ceases when the abutment Of thedashpot piston'e j- The admissionaofisteamav piston e bears against the dashpot piston e to the l t a -S d f p Piston 6 vwhi'c'h i's' held'fast 'in its-extreme right hand posiin 6 1 1 y Ofa 0' gitlon by controlling steam admitted to the re-' tudinal bore-r in thevslide lvalvearod'dyi whichversingspace"f through the pipe 7 By this rightiofi thepistofibl The steam which is-in the cylinder on the left hand side of the piston still" a p tures at bothl ends of the slide valve rod,' left hand movement of the main valve, the piston T s0 h 0r g 1' fo xamp ,th r'd clgses the passage a andthe steam exhaust controlling steamiintroducedcintotthe-reversmgyperiod is at' 'ar'i I end, compression commencing. agspace f can flow through the said bore T Jint01jFfiftherflmovement of the main valve 'pastthis thespa'ce'fi. 'Thelive steam-isindicated:in FigS. intermediate position, in'which both -steam pas- 1 t0 by.a' broken linefand the-,eXhauSt-by aydoti zsages a 'and af are' closed; is prevented owing to and'dash -i j v ,1 ,l the surface of 'thei-dashpot piston e which is This 5 method Of 50011131101 operatesoinxrthe fol-1 actedr-,uponby controlling vsteam beingnlarger plowing; manner: In Fig; 1ithe main islide valve- ':than theasumiofcthersurfacesiof'the pistons e is in the right hand end-position in which the-live: and c 1 steam can flow through:the-steamepassagea be- Figure 4shows-the-position :inzwhichthe pilot hind the power piston 17. The dashpot pi stons valve-t actuated bythe cam'3has uncovered the e and e are .alsoin; the; right hand endtposi t'ion; pipe r so-that the right hand side of the dashpot the left; hand surface of the: dashpot ,pistome t piston a has 1 steam \suppliedz toi it; and; :conse-r space through the pot piston 'e endio'f the cylind'er, withmeans for arresting the valve-in said initial cutoff position foriclosing the admission -port, -'Tcomprising a floating hollow dashr'io't' pistonfan abutment piston on the valve' and movable in}saidi dashpot piston in the line -quently"'-has moved to ithei left, :the main slide? valve being now in :its extreme lefthand posit The I passages 11 and a are both open'i Live steam ipas'ses dut-hOfth inlet aperture E 1 through the steam inlet passage'ra i behind? the pistoni b;. 1wm1e the used -.steaini'esbapes:- onthem against the ends of-i'the space within said'dash I pot piston, means 1 tor -arresting the valve 1 inan "intermediate positiorrfor closing the exhaust port ion regulating the -*compression} comprising a v floating hollow buffer "p'isttirnan' abutment piston on'the dashpot' piston and movable in" said buffer other side of the piston through "the: port-Ia" to r theexhaust a3. LThe mainslide valveiisapositively held' in' this position by "the control steam acting in the-reversing spacefi, and coming through the eipipes ml andl n from rthe pilot valves S and S M Figure 5' shows the Commencement of the expansion on the left hand side of the power piston b. The pilot valve S has opened the pipe m and permits the passage through it of the controlling steam into the reversing space F. By this means the main slide valve is moved until the abutment piston e bears against the dash-' Further movement to the right is prevented, since the dashpot pistons e and e are held stationary by steam admitted thereto through the pipes r and r The piston d has now closed the steam passage a and expansion commences. The passage a .is still open and steam still continues to flow out through it.

Figure 6 shows the position of the parts when compression on the right hand side of the piston is taking place. The pilot valve S controls the passage of live steam through the pipe n behind the piston e in the reversing space I from which steam passes through the pipe T in the valve rod behind the dashpot piston e while the controlling steam escapes from the reversing pipe n and pilot valve S to the exhaust T The reversing space f is evacuated through T The main valve moves to the right until the abutment piston e bears against the right hand side of the dashpot piston 6 which remains stationary in its extreme left hand position being by steam admitted to the reversing space i through the pipe r By means of this movement of the main valve, the passage a is closed and compression commences.

In order that the main slide valve will now move into the end position shown in Figure 1, the pipe r is evacuated through the pilot valve t ..The steam flowing, in through the pipe n into the reversing space I acts on the piston e and forces the mainvalve into its extreme right hand position. Both-passages a and a are opened.

Since the laps of the slide valve bodies (1 and d after the admission of steam at E in the second intermediate position are only small,

there is a practically constant admission of steam over a greater range of speeds for the same moment of opening and closing of the slide valve t What I claim is: p 1. In a reciprocating steam engine having a I steam cylinder 9, piston movable therein, a slide valve casing having inlet and exhaust ports in. open communication with said cylinder, a main slidevalve movable in saidslide valve casing for controlling the admission to and exhaust of steam, from said steam oylinder'a-nd controlling gear for said valve, comprising the combination of two pairs of differential pistons, conduits for supplying steam to one of the differential pistons of each pair for moving the valve into an initial, steam cut-on? position, conduits for supplying steam to the other difierential piston of each pair for moving theslide valve further into an end position for admitting steam to the opposite of moyement-of the-valve and capable of striking Q piston 'in j'thef'line of movement offthe valve and capable ofstriki'ng {against thee'nds' of the space 7 within said bufier piston, a conduit for admitting,

steam to the side of the dashpot piston adjacent the valve, said dashpot piston being adapted to obstruct communication between said conduit and said side of thedashpot piston when the mainvalve is located in-the end position into which it is moved by steam supplied to the second-mentioned difierential piston of; the pair,

remote from the dashpot piston, a conduit for admitting steam to the adjacentsides of the buffer and dashpot pistons, a conduit for admit,-

-ting steam to the other side of the buffer piston remote from the dashpot piston, and pilot valves 7 interposed in said conduits for controlling the supply of steam to the said diiferential pistons,

and the supply of steam successively to said dashpot piston andbuffer piston for arresting the valve in said initial and intermediate'positions and subsequently allowing the valve to move into said end position for admitting steam to the op- A posite end of the cylinder, saidpilot valvesbeing operatively connected to the engine piston so as to be positively actuatable thereby.

2. In a reciprocating steam engine having a differential pistons of each pair, conduits for sup-;

plying steam to said reversing spaces and a pilot valve for controlling the steam supply to said conduits alternately for moving the valve into an end position for admitting steam to one endiof the cylinder, reversing spaces adjacent the other difierential pistons of each pair, conduits for supplying steam to said other reversing spaces and a second pilot valve for controlling the 'steam supply to said conduits alternately for moving the valve into aninitial'cut-off position, with a floating hollowdashpot piston, an abutment piston on the main valve and movable insaid dashpot piston in the line of movement of the valve and capable of striking against the ends of the space within said dashpot piston for arresting the main valve in said initial steam cut-01f position, a floating hollow bufier piston, an abutment piston on the dashpot piston and. movable in said buffer piston in the line of movement'of the main valve and capable of striking against the ends of the space within said bufier piston for arresting the main valve in an intermediate position for closingthe exhaust port for regulating the compression, a; conduit in the main valve for admitting steam to the side of 'the dashpot piston adjacent the main valve, said dashpot piston being adapted to obstruct com- Iocatedsin the: end position into which-it ismo-ved:-

iothentdifierential ipistonzoftthe :other pain" by 'steam supplied: to therfirst-mentioned: differential piston of' the' pair .remote;from the dashpot -piston;. a conduit connected-to the "first pilot valve forlsupplying steam to. the :adjacent sides I of: the izdashpot: andybufierzpistons; athird pilot valve;- anda; rconduit"connectedthereto for supplyingasteam to the side of the-buffer piston-remote from: .the; dashpot piston;- and actuating means 'ffom saidwpiloti valves aoperatively connected-toathekz engine piston and: arranged to} operate the ".-first',-pi1ot-* valve 2:130 :admit steam to munication:ibetweenrrsaid c'onduit randwvsaid side. ofn thew-dashpot: piston when ;:the.;main-' valve-sis:

'rtheereversing space adjacentitheronedifferential vpistor'riofone*paircandethewsecond zpilotwalv'ezto :admit steamttocthemeversing vspace adjacentrthe'? 3.;1Inua, creciprocatingrsteam engine, the combina,tion-. as .1 setzforthuin iclaim :2, in 'which" the actuatingameans z'fonwnthe rpilot valves: comprise a adrivinglsh'aft' and-oblique cams mounted on saiclr drivingzshacft tsoatasto be :capable of sliding;

axiallythereon andxiarrangecl to coact withythe 10' "pilot valves in difierent-axial positions zonusaidm shaft. FRI'IZ'FIOLKIENJ: 

